Electrically propelled light service vehicles offer obvious advantages over gasoline powered cars from the standpoint of noise and pollution. Nevertheless, they have had limited success in competing with gasoline vehicles because of distance and performance limitations associated with reasonable restriction of the number of batteries required to be used at a time, reasonable service life for the batteries, and cost and inconvenience of recharging and keeping track of which vehicles are charged, and to what degree, during periods of heavy demand for use.
The present invention provides a light service vehicle that is superior in these respects. For example, when used as a golf car, the vehicle can carry a payload of two passengers and golf bags for well over 36 holes on a golf course using four batteries of standard electric vehicle type. With two batteries the loaded vehicle will go well over 18 holes.
The vehicle of the invention is provided with a quick-change battery pack loadable and unloadable over the rear of the vehicle by a light manually operated dolly. By providing an excess of battery packs for a fleet of vehicles, recharging can proceed independently of use of the vehicles.
When the vehicle is used as a golf car with a two-battery pack, the vehicle will complete 18 holes with a comfortable margin of reserve. At the end of every 18 holes a fresh battery pack can be installed in a matter of seconds for the next 18 holes of operation. With a four-battery pack, the vehicle will complete 36 holes with a comfortable margin of reserve. A fresh pack can then be installed if further service is required that same day. Or, four-battery packs can be interchanged every 18 holes to further extend battery life and reduce recharge time.
In the vehicle of the invention, the axle associated with the drive wheels may be non-rotating and fixed near each end to a tubular side frame member. The axle may bend and the frame members twist under the loading imposed by the weight of the vehicle frame, batteries and payload. This relatively stiff springing is supplemented by softer springing of the passenger seats and luggage carrying racks with respect to the vehicle frame. This stiff springing arrangement with respect to the vehicle frame and batteries but not the passengers and payload allows a substantial saving in the overall weight of the vehicle without sacrifice of reasonable passenger comfort. This contributes to achievement of good accelleration and braking and good operating economy for the vehicle whether used as an on-the-road vehicle such as a suburban runabout or an off-the-road vehicle such as a golf car. When the vehicle is used as a golf car, the light weight also reduces the potential for damage to the golf course when the ground is soft and allows quicker resumption of vehicle use following adverse climatic or seasonal conditions.
Also contributing to the operating economy of the vehicle is the power system of the vehicle. This power system also contributes importantly to good traction and steerability of the relatively light vehicle under all operating conditions. For on-the-road applications, the power system allows good control of accelleration and decelleration in street traffic under all conditions, including ice and snow. These contributions will be more fully described in the description of the illustrated embodiment of the invention set forth below.